updncnt.v

universal count un iversal count

module UpDnCnt (input en,clr,clk,ld,up,dn, 
                  input  [3:0] d,
                  inout  [3:0] q);
                  
  reg [3:0] q_int;


assign  q = (en) ? q_int : 4'bzzzz;
               
  always @ (posedge clk) begin
	if (clr==0)
		q_int=4'b1111;
	
    else if (ld==1 && up==0 && dn==0)
	q_int = d ;
	
	else if (ld==0 && up==1 && dn==0)
	q_int = q + 1;
	
	else if (ld==0 && up==0 && dn==1)
	q_int = q - 1;
	
	else
	
	q_int = q ;
	
	end
	
endmodule